ROMANYUK, A. S.; YANCHENKO, S. Ya. Approximation of classes of periodic functions in one and many variables from the Nikol’skii – Besov and Sobolev spaces. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 74, n. 6, p. 844–855, 2022. DOI: 10.37863/umzh.v74i6.7141. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/7141. Acesso em: 5 dec. 2025.